Empirical scavenging coefficients of radioactive substances released from Chernobyl

After the accident at the Chernobyl power plant on 26 April 1986, most parts of Europe were affected by the associated radiation pollution. In this paper the dependence of the precipitation scavenging coefficient λ (s-1) on the rainfall rate R (MM h-1) is studied on the basis of radioactivity and radar rainfall measurements in Southern Finland after the accident. The average scavenging coefficient weighted by the high-altitude concentration of radionuclides involved was found to be λ = 10-4 s-1 R0.64, in good agreement with earlier investigations. The results also suggest that weather radar may form an important and effective part of a real-time radiation monitoring and warning system. (author)